Position-Based Limited-Response Mode Operation in a Vehicle Communication System

ABSTRACT

A communication system for facilitating control over a function of a vehicle ( 102 ) comprises a base station ( 104 ) positioned in the vehicle ( 102 ) and a mobile communication unit ( 122 ). The base station ( 104 ) comprises a first transmitter for transmitting a signal to the mobile communication unit ( 122 ) and a first receiver for receiving a signal from the mobile communication unit ( 122 ). The base station ( 104 ) is configured to determine a location of the mobile communication unit ( 122 ) relative to the vehicle ( 102 ) and to cause the mobile communication unit ( 122 ) to operate in accordance with a limited-response mode when the location of the communication unit relative to the vehicle ( 102 ) remains substantially unchanged for a predetermined period of time.

TECHNICAL FIELD

The present invention relates to a vehicle communication system forfacilitating control over vehicle functions. The present inventionrelates more particularly, but not exclusively, to systems and methodsfor facilitating control over vehicle functions based, at least in part,on position of a mobile communication unit. Aspects of the inventionrelate to a system, to a method and to a vehicle.

BACKGROUND OF THE INVENTION

In today's world, many vehicles are equipped with systems forfacilitating remotely controlled vehicle functions such as passive entryand passive starting (i.e., PEPS) of a host vehicle. When a vehicle isequipped with a PEPS system, a user carries a mobile communication unitwhich can communicate with a base station located in the vehicle. Toconserve use of energy stored in its internal battery, system componentsmay remain in a low power state until an initiating trigger (forexample, manipulation of a vehicle door handle) awakens one or moreother system components. For example, upon sensing that a door handlehas been manipulated, the base station may emit a relatively powerfulLow Frequency (LF) electromagnetic field, causing a mobile communicationunit that is sufficiently close to the base station to awaken. Once themobile communication unit is awake, it may use Radio Frequency (RF)transmissions (i.e., communications) to dispatch a response signal,which may be validated by the base station. If the base stationrecognizes and approves the identity of the mobile communication unit,(i.e., the base station authenticates the mobile communication unit),the base station may facilitate the performance of a predefined vehiclefunction, such as actuating a door lock mechanism, causing the door tobecome unlocked.

Because the amount of energy required by the base station to generate aLF field is significant, many such systems employ a sleep mode andawaken only upon the occurrence of a trigger event. Unfortunately, theuse of an initiating trigger necessitates that the sequence ofauthenticating the mobile communication unit be performed within anextremely short amount of time so as to avoid delays in response fromthe vehicle. Fast-release motors may be employed to perform theactuation functions such as unlocking a door.

Means may be provided for monitoring movements of the mobilecommunication unit such that, after a period of time in which the mobilecommunication unit has remained stationary and has not been otherwiseactivated, the mobile communication unit would be caused to enter thesleep mode. Unfortunately, when the mobile communication unit is in thevehicle, physical movements of the vehicle may be misinterpreted asmovements of the mobile communication unit even though the mobilecommunication unit may be stationary with respect to the vehicle. Underthose circumstances, the misinterpreted vehicle movements may preventthe mobile communication unit from entering the sleep mode whenever thevehicle is moving.

The present invention attempts to address or ameliorate at least some ofthe above problems associated with vehicle communication systems.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides a communication system forfacilitating control over a function of a vehicle comprising a basestation positioned in the vehicle and a mobile communication unit. Thebase station comprises a first transmitter for transmitting a signal tothe mobile communication unit and a first receiver for receiving asignal from the mobile communication unit. The base station isconfigured to determine a location of the mobile communication unitrelative to the vehicle and to cause the mobile communication unit tooperate in accordance with a limited-response mode when the location ofthe communication unit relative to the vehicle remains substantiallyunchanged for a predetermined period of time.

The base station may be configured to cause the mobile communicationunit to operate in accordance with a limited-response mode when thelocation of the communication unit relative to the vehicle remainswithin an authorization zone for a predetermined period of time.Accordingly, the invention provides for conserving energy stored in thebattery of the mobile communication unit and unnecessary exercising ofvehicle functions.

The base station may be configured to cause the mobile communicationunit to operate in accordance with a limited-response mode when thelocation of the communication unit relative to the vehicle is within anauthorization zone and remains relatively unchanged for a predeterminedperiod of time. The base station may be configured to cause the mobilecommunication unit to operate in accordance with a limited-response modewhen the location of the communication unit relative to the vehicle iswithin an authorization zone and the vehicle remains free frominterruption for a predetermined period of time.

The mobile communication unit may comprise a motion sensor configuredfor detecting a movement of the mobile communication unit and foroutputting a signal indicative of the movement. The signal may be sentto the base station. The base station may be configured to receive saidsignal indicative of a motion of the mobile communication unit and tocause the mobile communication unit to operate in accordance with alimited-response mode when the signal is indicative of the motionsatisfying a predetermined limited-response criteria. The predeterminedlimited-response criteria may comprise freedom from movements exceedinga threshold level of at least one of a frequency, a distance/magnitude,a velocity or an acceleration magnitude.

The base station may be configured to receive the signals indicative ofa motion of the mobile communication unit and to cause the mobilecommunication unit to resume operating in accordance with ahigh-response duty cycle when said signal is indicative of said motionsatisfying a predetermined high-response criteria. The predeterminedcriteria may be based on a frequency of the motion. The predeterminedcriteria may also be based on a magnitude of the motion.

The base station may be configured to cause a sensitivity of the motionsensor to be adjusted. The base station may be configured to cause asensitivity of the motion sensor to be adjusted when the location of thecommunication unit relative to the vehicle remains substantiallyunchanged for a predetermined period of time. Further, the base stationmay be configured to cause a sensitivity of the motion sensor to beadjusted when the location of the communication unit relative to thevehicle remains within an authorization zone for a predetermined periodof time.

The base station may be configured to cause a sensitivity of the motionsensor to be adjusted when the location of the communication unitrelative to the vehicle is within an authorization zone and remainsrelatively unchanged for a predetermined period of time. The basestation may also be configured to cause a sensitivity of the motionsensor to be adjusted when said signal is indicative of the motionsatisfying a predetermined, limited-response criteria. The predeterminedlimited-response criteria may comprise freedom from movements exceedinga threshold acceleration magnitude. The predetermined criteria may bebased on a frequency of said motion, on a magnitude of said motion, oron a duration of said motion.

The base station may be configured for determining a location of themobile communication unit relative to the vehicle based on either a timeof flight of communications between the mobile communication unit andthree or more transceivers positioned in the vehicle or a time of flightof an ultra-wide band communication between the mobile communicationunit and the three or more transceivers positioned in the vehicle.

The limited-response mode may comprise the mobile communication unitoperating in accordance with a limited-response duty cycle. Thelimited-response duty cycle may comprise a transceiver of the mobilecommunications unit having active phases which are interrupted byperiods of inactivity. In this way, the overall time for which thetransceiver is active may be reduced compared to when the mobilecommunication unit operates in accordance with a high-response dutycycle. Alternatively, the limited response mode may comprise a sleepmode in which a transceiver of the mobile communication unit is inactivewith no intermittent periods of activity.

In a further aspect, the present invention provides a method offacilitating control over a function of a vehicle comprising providing abase station positioned in the vehicle and a mobile communication unit,wherein the base station comprises a first transmitter and a firstreceiver. A signal is transmitted from the first transmitter to themobile communication unit, and a signal is received from the mobilecommunication unit. A location of the mobile communication unit relativeto the vehicle is determined, and, when the location of the mobilecommunication unit relative to the vehicle remains substantiallyunchanged for a predetermined period of time, the mobile communicationunit is caused to operate in accordance with a limited-response mode.The step of causing the mobile communication unit to operate inaccordance with a limited-response mode may be performed either when thelocation of the mobile communication unit relative to the vehicleremains within an authorization zone for a predetermined period of timeor when the location of the mobile communication unit relative to thevehicle is within an authorization zone and remains relatively unchangedfor a predetermined period of time or alternatively when the location ofthe mobile communication unit relative to the vehicle is within anauthorization zone and the vehicle remains free from interruption for apredetermined period of time.

The method may comprise detecting a movement of the mobile communicationunit and outputting a signal indicative of the movement. The method maycomprise receiving the signal indicative of a motion of the mobilecommunication unit such that causing the mobile communication unit tooperate in accordance with a limited-response mode may be performed whenthe signal is indicative of the motion satisfying a predeterminedlimited-response criteria. Said predetermined limited-response criteriamay comprise freedom from movements exceeding a threshold accelerationmagnitude. The predetermined limited response criteria may be based on afrequency of said motion, on a magnitude of said motion, or on aduration of said motion.

The method may comprise receiving the signal indicative of a motion ofthe mobile communication unit and, when the signal is indicative of themotion satisfying a predetermined high-response criteria, causing themobile communication unit to resume operating in accordance with ahigh-response duty cycle. The predetermined high-response criteria maybe based on a frequency or magnitude of said motion. The detecting amovement of the mobile communication unit may be performed using amotion sensor such that a sensitivity of the motion sensor may be causedto be adjusted. A location of the mobile communication unit relative tothe vehicle may be determined based on a time of flight ofcommunications between the mobile communication unit and three or moretransceivers positioned in the vehicle.

In another aspect, there is provided a vehicle having a communicationsystem as described in the foregoing aspects which may be adapted toperform a method, as described in the preceding aspects.

Within the scope of this application it is envisaged that the variousaspects, embodiments, examples, features and alternatives set out in thepreceding paragraphs, in the claims and/or in the following descriptionand drawings may be taken independently or in any combination thereof.For example, features described in connection with one embodiment areapplicable to all embodiments unless there is incompatibility offeatures.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the present invention will now be described,by way of example only, with reference to the accompanying figures, inwhich:

FIG. 1 shows a schematic representation of a vehicle communicationsystem according to an embodiment of the present invention;

FIG. 2 shows the installation of the base station and transceivers ofthe vehicle communication system according to one embodiment of thepresent invention in a motor vehicle;

FIG. 3 shows an operating mode of the vehicle communication systemaccording to one embodiment of the present invention;

FIG. 4 illustrates another operating mode of the vehicle communicationsystem according to one embodiment of the present invention;

FIG. 5 illustrates another operating mode of the vehicle communicationsystem according to one embodiment of the present invention; and

FIG. 6 illustrates another operating mode of the vehicle communicationsystem according to one embodiment of the present invention.

DETAILED DESCRIPTION

FIG. 1 shows a vehicle communication system 100 in accordance with anembodiment of the present invention. The vehicle communication system100 is configured to facilitate transfer of information among componentsof the vehicle communication system 100, which may further facilitatecontrol over one or more functions of a vehicle 102. Exemplary functionsthat may be controlled include, but are not limited to, enhanced PassiveEntry and Passive Start (ePEPS) keyless access, remote engine start,remote opening and closing of vehicle apertures, deployment andretraction of external mirrors or antennas, and/or activation anddeactivation of lighting and signalling systems of the vehicle 102.

The vehicle communication system 100 will be described with reference tothe vehicle 102 which has a front right door 142, a rear right door 144,a front left door 146 and a rear left door 148. The vehicle 102 also hasa boot lid 150 (also known as a deck lid) which can be locked/unlockedby the vehicle communication system 100 but this is not described hereinfor the sake of brevity. The doors 142-148 each have a lock mechanismand an external handle; and the front doors 142, 146 each have a foldingdoor mirror. The lock mechanisms each comprise a door lock switch toprovide a locking signal to indicate the status of the respective lockmechanism.

The vehicle communication system 100 comprises a base station 104 to beinstalled in the vehicle 102 to provide a Remote Function Actuator (RFA)for the vehicle 102. The base station 104 comprises an electroniccontrol unit 106 and a first rechargeable battery 108. The electroniccontrol unit 106 comprises a memory storage device 107 that is incommunication with one or more processor(s) 109. The processor(s) 109can be configured to perform computational instructions stored in thememory storage device 107. The first rechargeable battery 108 provides adedicated power supply for the base station 104 to enable its operationindependently from a vehicle power system (not shown).

The base station 104 further comprises first, second and thirdultra-wideband transceivers 110, 112, 114. The first transceiver 110 isprovided proximal the electronic control unit 106. The second and thirdtransceivers 112, 114 are positioned in the vehicle 102 remote from theelectronic control unit 106 and connected via a dedicated localinterconnect network (LIN) 116. The transceivers 110, 112, 114 each havean integrated antenna. As discussed more fully below, the vehiclecommunication system 100 may further comprise a fourth transceiver (notshown) which is also positioned in the vehicle 102 remote from theelectronic control unit 106 and connected via the dedicated localinterconnect network (LIN) 116.

The base station 104 is connected to the vehicle systems (denotedgenerally by the reference numeral 118) via a CAN bus 120. The basestation 104 can thereby receive signals from the vehicle systems (e.g.,locking signals from door lock switches); and can control operation ofone or more vehicle systems (e.g., door lock mechanisms, closure systemsfor vehicle apertures such as windows, sun roof, ventilation systems,deck lid, engine start/ignition, vehicle lighting, entertainmentsystems, horn, heater, air conditioning, and the like). The CAN bus 120can also be employed to convey instructions from the electronic controlunit 106 to other systems (e.g., actuators, controls) of the vehicle102, such as the engine control unit, to facilitate enabling and/ordisabling of one or more vehicle systems (e.g., passive enginestarting).

The vehicle communication system 100 further comprises a mobilecommunication unit 122 having a remote ultra-wideband transceiver 124and a second rechargeable battery 126. The mobile communication unit 122is portable to facilitate its being carried by the user. As describedherein, the mobile communication unit 122 communicates with the basestation 104 to facilitate control over vehicle functions, such aspassive entry to the vehicle 102, and, under some circumstances, toprovide information to a user in possession of the mobile communicationunit 122.

The base station 104 further comprises a dock 128 for receiving themobile communication unit 122. The dock 128 has a port 130 to enablecommunication between the base station 104 and the mobile communicationunit 122. A charging pad 132 is also provided in the dock 128 tofacilitate charging of the second rechargeable battery 126 when themobile communication unit 122 is docked and thus mated with the chargingpad 132. A bi-colour light emitting diode 134 is provided in the dock128 to indicate the status of the mobile communication unit 122 (forexample to indicate that the second rechargeable battery 126 is chargingor is fully charged). The charging pad 132 is connected to a powersupply unit (PSU) provided in the base station 104. An external chargeport 136 for the base station 104 is provided for charging the firstrechargeable battery 108.

The installation of the vehicle communication system 100 is illustratedin FIG. 2. The base station 104 and the first transceiver 110 arelocated at the rear of the vehicle 102 and the second and thirdtransceivers 112, 114 are located in the upper part of the vehicle 102(typically in the roof) on the right and left sides respectively of thevehicle 102. As illustrated by dashed lines in FIG. 2, the transceivers110, 112, 114 communicate with the mobile communication unit 122. Thedistance from each of the first, second and third transceivers 110, 112,114 to the remote transceiver 124 can be determined by measuringtransmission and/or response time (for example, time of flight for asignal transmission) thereby allowing the position of the mobilecommunication unit 122 in relation to the vehicle 102 to be determinedthrough triangulation. The use of ultra-wideband frequencies (typicallygreater than 3 GHz) allows the position of the mobile communication unit122 to be tracked with a relatively high degree of accuracy.

In accordance with such an embodiment of the vehicle communicationsystem 100, wherein the base station 104 comprises three transceivers110, 112, 114 disposed at spaced apart locations within the vehicle 102,it is possible to use the transmission and/or response times forcommunications sent between the mobile communication unit 122 and eachof the transceivers 110, 112, 114 to determine a position of the mobilecommunication unit 122 relative to the vehicle 102 along each of twoaxes. For example, with the base station 104 and the first transceiver110 located toward the rear of the vehicle 102 and the second and thirdtransceivers 112, 114 disposed within the roof (on respective left andright sides), the position of the mobile communication unit 122 relativeto the vehicle 102 can readily be determined, i.e. as shown in the planview of FIGS. 2 to 6.

However, with the second and third transceivers 112, 114 disposed in thevehicle roof, and therefore lying in the same horizontal plane, theremay be situations in which it is not possible to readily determine theposition of the mobile communication unit 122 along a direction normalto the plan views of FIGS. 2 to 6. Accordingly, in a further embodimentof the invention, the vehicle communication system 100 may comprise afourth transceiver (not shown) which is disposed within the vehicle 102at a location which is spaced apart in a vertical direction from boththe plane of the vehicle roof and the horizontal plane in which the basestation 104 lies. For example, the fourth transceiver (not shown) couldbe mounted in the vehicle dashboard on the vehicle center line. Withthis configuration, the height of the mobile communication unit 122relative to the vehicle 102 can readily be determined.

Thus, a position of the mobile communication unit 122 relative to thevehicle 102 may be periodically or continuously determined and may besaved in the memory storage device 107 for subsequent retrieval andanalyses by the processor 109. Such monitoring and storing andprocessing of position information may be useful for observing,tracking, and identifying certain rates, patterns, and/orcharacteristics of movement. For example, the vehicle communicationsystem 100 may be configured to detect an approach of the mobilecommunication unit 122 toward an authorization zone 138 definedrelatively to the vehicle 102, to detect a departure of the mobilecommunication unit 122 from the authorization zone 138, to detect acontinuing presence of the mobile communication unit 122 within theauthorization zone 138, and to recognize patterns involving combinationsof approaches, departures, and prolonged presences relative to theauthorization zone 138 of the vehicle 102.

The remote transceiver 124 of the mobile communication unit 122transmits a polling signal which, when received by the first transceiver110 of the base station 104, initiates communication between the basestation 104 and the mobile communication unit 122. In one embodiment,upon receipt of the polling signal, the first transceiver 110 respondsby transmitting a challenge signal. The challenge signal is received bythe mobile communication unit 122 and prompts the mobile communicationunit 122 to transmit a response signal. The electronic control unit 106receives the response signal and attempts to determine whether it wassent by an authorized device (i.e., to validate or authenticate themobile communication unit 122).

If the response signal is authenticated, the electronic control unit 106continues to communicate with the mobile communication unit 122 andtracks its position in relation to the vehicle 102 and may store theposition information in the memory storage device 107 for retrieval andprocessing by the processor 109 in accordance with pre-definedinstructions. Moreover, provided the challenge/response sequence iscompleted successfully, the electronic control unit 106 will providecontrol over functions of the vehicle 102 subject to satisfaction ofoperating criteria. If the response signal is not authenticated, theelectronic control unit 106 will not facilitate user control overvehicle functions, such as unlocking the doors of vehicle 102 orstarting the engine of vehicle 102.

In one mode of operation, the polling signal is transmitted continuallyby the remote transceiver 124 so that communication with the basestation 104 is initiated by the mobile communication unit 122.Accordingly, the vehicle communication system 100 can initiate achallenge/response cycle without the need for user interaction, such asactuating a door handle.

In another mode of operation, such as may be active upon first entry ofthe vehicle 102 into service, to conserve energy stored in the secondrechargeable battery 126, the polling signal is transmitted for anoperating period of thirty (30) days. The transmission of the pollingsignal is stopped if the mobile communication unit 122 does notestablish communication with the base station 104 during the operatingperiod. A button provided on the mobile communication unit 122 can bepressed to re-commence transmission of the polling signal after saidoperating period has expired.

In another embodiment, the polling signal is transmitted intermittently,rather than continuously. In accordance with this embodiment, thepolling signal is repeated during the operating period with a timeinterval between transmission cycles (pulses), i.e. the polling signalis transmitted periodically during the operating period. The timeinterval between the transmission cycles can be modified in response tomeasured parameters. For example, the time interval betweencommunications can be modified depending on the measured distancebetween the vehicle 102 and the mobile communication unit 122. Forexample, if the mobile communication unit 122 is close to the vehicle102, the time interval can be reduced to one (1) second. Conversely, ifthe mobile communication unit 122 is relatively far away from thevehicle 102, the time interval can be increased to five (5) seconds.

The base station 104 and the mobile communication unit 122 cancommunicate with each other over a range of at least 20 metres. Theauthorization zone 138 is defined within the communication range. Forexample, the authorization zone 138 may be defined as having a radius of2 metres around the vehicle 102. When the electronic control unit 106determines that the mobile communication unit 122 is inside theauthorization zone 138, the base station 104 may facilitate automaticunlocking of one or more of the vehicle's doors 142-148. Conversely,when the electronic control unit 106 determines that the mobilecommunication unit 122 is outside the authorization zone 138, the basestation 104 may cause the automatic locking of the vehicle's doors142-148.

As discussed above, a vehicle communication system 100 comprising threeor fewer transceivers may be able to determine a position of the mobilecommunication unit 122 relative to the vehicle 102 along only two axes.Accordingly, the authorization zone 138 may be defined in terms of onlythose two axes. A vehicle communication system 100 comprising four ormore transceivers, however, may be able to determine a position of themobile communication unit 122 relative to the vehicle 102 along anycombination of three (optionally orthogonal) axes. Accordingly, thelocation of the authorization zone 138 may be defined in terms positionsalong each of the three axes, such that the authorization zone 138 (andthus the set of locations that are outside the authorization zone 138)may be defined in terms of three-dimensional space relative to thevehicle 102.

Being able to accurately determine the position of the mobilecommunication unit 122 in a three-dimension space around the vehicle 102may be particularly useful in certain situations, for example when thevehicle 102 is parked in a multi-level or multi-story car park oradjacent to a multi-story building. In such situations it is possiblethat the driver, having exited the vehicle 102 may move to another levelof the car park or building above or below the vehicle 102, but maystill be sufficiently close to the vehicle 102 to be within theauthorization zone 138, resulting in one or more of the vehicle doorsbeing unlocked.

Accordingly, if it is determined that the mobile communication unit 122is disposed sufficiently above or below the vehicle 102, such as in theexample of the multi-level car park, the electronic control unit 106 maynot unlock the vehicle doors even when the mobile communication unit 122would otherwise be judged to be within the authorization zone 138.

The electronic control unit 106 may be configured to operate the vehiclecommunication system 100 according to a number of operating modes. In anumber of scenarios, the mobile communication unit 122 is carried on theperson of the user and therefore follows the movements of the user. Inthe accompanying figures, movement paths of the user, and therefore, themobile communication unit 122, are illustrated by a set of footprints140. The process performed by the base station 104 for authenticatingthe mobile communication unit 122 is the same as described above and iscommon to each of the operating modes.

In particular, the remote transceiver 124 transmits a polling signalwhich initiates an authentication cycle with the first transceiver 110.The base station 104 transmits a challenge signal which triggerstransmission of a response signal from the mobile communication unit122. The electronic control unit 106 validates the response signal and,if successful, the base station 104 tracks the range and position of theauthenticated mobile communication unit 122. If the authentication cycleis not successfully completed, for example due to an incorrect responsesignal being sent from the mobile communication unit 122, the doors142-148 will not be unlocked, and the vehicle 102 will not respond tothe mobile communication unit 122.

The electronic control unit 106 may be configured to operate the vehiclecommunication system 100 according to a first operating mode asillustrated in FIG. 3. In this operating mode, the vehicle communicationsystem 100 operates to unlock the doors 142-148 on the side of thevehicle 102 on which the user approaches with the mobile communicationunit 122. Having authenticated the mobile communication unit 122, thebase station 104 tracks the range and position of the mobilecommunication unit 122. In the illustrated example, the electroniccontrol unit 106 determines that the mobile communication unit 122 is onthe right hand side of the vehicle 102. Once the base station 104determines that the mobile communication unit 122 is within theauthorization zone 138, the electronic control unit 106 automaticallygenerates a door unlock signal to unlock both doors 142, 144 on theright hand side of the vehicle 102. The door unlock signal istransmitted via the CAN bus 120, and the front right door 142 and therear right door 144 are both unlocked when the mobile communication unit122 enters the authorization zone 138. As the doors 142, 144 areunlocked before the user operates the respective door handle, in normaloperating conditions it is envisaged that there would be no perceptibledelay when the user operates the door handle.

In this mode, when the user operates the door handle on either the frontright door 142 or the rear right door 144, either a single-point entry(SPE) or a multiple-point entry (MPE) can be initiated. In single-pointentry mode, when the drivers door is the only opened door and the keyfob is taken into the vehicle, the rear door on the approached side willbe re-locked. For the avoidance of doubt, the drivers door does not haveto be closed to effect the locking of the rear door. If ANY door otherthan driver's door is opened, then all doors will be unlocked and remainso. The action of locking the rear door on the driver's side is causedby the key fob being detected inside the vehicle and thus no longer seenin the authorisation zone on the outside of the vehicle. In amultiple-point entry, the electronic control unit 106 generates controlsignals to unlock all of the other doors in the vehicle 102 when thedoor handle of either the front right door 142 or the rear right door144 is operated. It will be appreciated that the front left door 146 andthe rear left door 148 will be unlocked if base station 104 determinesthat the mobile communication unit 122 enters the authorization zone 138on the left hand side of the vehicle 102. Only when the door handle ofone of the unlocked doors 142-148 is operated is an indication providedthat the doors have been unlocked, for example by flashing the siderepeaters and/or extending the door mirrors. If none of the door handlesare operated, however, no indication is provided that one or more of thedoors 142-148 have been unlocked.

The electronic control unit 106 may be configured to operate the vehiclecommunication system 100 according to a second operating mode asillustrated in FIG. 4 to accommodate a walk-past scenario. In thiswalk-past scenario, the user enters and exits the authorization zone 138but does not operate a door handle. As in the first mode describedabove, the base station 104 authenticates the mobile communication unit122 as it approaches the vehicle 102. In this case, the base station 104tracks the position of the mobile communication unit 122 and determinesthat the user is approaching from the rear of the vehicle 102 on theright hand side. As described above in regard to the first mode ofoperation, when the vehicle communication system 100 detects that themobile communication unit 122 has entered the authorization zone 138, asit has in this walk-past scenario, a door unlock signal is transmittedto unlock the front right door 142 and the rear right door 144.

In this scenario, however, the user does not operate the door handle oneither of the doors 142, 144 and, instead, walks past the vehicle 102.Since the vehicle communication system 100 is tracking the position ofthe mobile communication unit 122, the vehicle communication system 100is able to determine when the mobile communication unit 122 leaves theauthorization zone 138. Accordingly, upon the departure of the mobilecommunication unit 122 from the authorization zone 138, and lacking thereceipt of any indication that a door handle has been operated, the basestation 104 transmits a door lock signal to lock the front right door142 and the rear right hand door 144 or otherwise facilitates there-locking of those doors. In one embodiment, the vehicle 102 does notprovide a visual indication when the doors 142, 144 are unlocked orsubsequently locked.

The electronic control unit 106 may be configured to operate the vehiclecommunication system 100 according to a third operating mode asillustrated in FIG. 5 to facilitate the automatic locking of the doors142-148 when the user walks away from the vehicle 102. In this scenario,the user exits the vehicle 102 carrying the mobile communication unit122 and closes the vehicle doors 142-148. In the illustrated example,the user exits the vehicle 102 through the front right door 142 and thencloses it. The user then walks away from the vehicle 102 carrying themobile communication unit 122. As the mobile communication unit 122 iscarried away from the vehicle 102, the vehicle communication system 100tracks the location of the mobile communication unit 122 and comparesthat location to the definition of the authorization zone 138. If andwhen the vehicle communication system 100 determines that the mobilecommunication unit 122 has left the authorization zone 138, the vehiclecommunication system 100 transmits a door lock signal to lock the doors142-148. The vehicle 102 is thereby secured automatically without theuser activating the mobile communication unit 122 or taking any actionother than walking away from the vehicle 102. A security protocol tocomply with industry standards, for example those specified byThatcham®, would typically be undertaken for the automatic locking ofthe doors 142-148. Under normal operating conditions, the automaticlocking of the vehicle 102 does not double-lock the vehicle 102. Rather,the vehicle 102 would only be double-locked if the user specificallyselected this locking mode, for example via a control panel in thevehicle 102.

The electronic control unit 106 may be further configured to operate thevehicle communication system 100 according to a fourth operating mode asillustrated in FIG. 6 to accommodate a mis-lock scenario. This mode issimilar to the third operating mode described above insofar as the userexits the vehicle 102 through the front right door 142 and closes thedoor 142 before walking away from the vehicle 102. In connection withthis fourth operating mode, the vehicle communication system 100 againdetermines if and when the mobile communication unit 122 has departedthe authorization zone 138. As illustrated in FIG. 6, however, the rearleft door 148 is ajar, and the electronic control unit 106 determinesthat the door 148 cannot be locked (a so-called mis-lock).

To avoid the user leaving the vehicle 102 in an unsecure state (as mayotherwise occur if the operator had not noticed that the rear left door148 was ajar) the electronic control unit 106 transmits an alert signalto the CAN bus 120 and a notification is provided to the user. Forexample, the CAN bus 120 may illuminate the side repeaters and/orprovide an audible warning to notify the user that the doors 142-148have not all been locked. When the rear left door 148 is closed, thevehicle communication system 100 will lock the door 148 to secure thevehicle 102.

In conjunction with the above-described modes of operation, theelectronic control unit 106 may be configured to operate the vehiclecommunication system 100 according to a fifth operating mode,accommodating a picnic scenario. In order to conserve energy stored inthe second rechargeable battery 126 of the mobile communication unit122, to avoid unintended and unnecessary actuation of vehicle systems,and to conserve energy in the components of the system, it may bedesirable, in certain situations, for one or more components of thevehicle communication system 100, such as the mobile communication unit122, to operate in a modified, energy-conserving manner. For example,when the mobile communication unit 122 has remained substantiallystationary relative to the vehicle 102 for greater than a predeterminedperiod of time, yet remains in a location within the authorization zone138, it may be determined that the likelihood of an immediate and urgentneed for two-way communication involving the mobile communication unit122 may be relatively low. Accordingly, it may be desirable for the basestation 104 to be able to determine whether certain criteria for apicnic scenario have been met and, if so, to instruct the mobilecommunication unit 122 to enter a reduced-sensitivity, energy-conservingpicnic mode.

In support of the ability to discriminate between the picnic scenario(wherein a slower response time may be acceptable) and other modes (inwhich a relatively fast response time is deemed necessary), the basestation 104 is configured to recognize attributes of a picnic scenario.These attributes may be characterized based on experience. For example,it is anticipated that a picnic scenario is appropriately identifiedwhen: (1) the mobile communication unit 122 remains present within theauthorization zone 138 for a time period (i.e., a residence period) thatexceeds a predetermined threshold length of time; and (2) during theresidence period, the vehicle 102 remains free from interruption (i.e.,a user does not attempt to gain access to the vehicle 102 and issues nocommands to the vehicle 102—either passively or actively). An activecommand would include pressing a button to initiate a remote start or toopen or close a window or the sunroof. A passive command would includeentering or exiting the authorization zone 138. Upon recognition of apicnic scenario, the base station 104 is configured to command themobile communication unit 122 to enter a limited-response mode. In otherwords, the mobile communication unit 122 enters a sleep mode.

As described above, the mobile communication unit 122 may contain aninternal motion sensor 152 configured for detecting movements of themobile communication unit 122 and sending signals indicative of thosemovements. The mobile communication unit 122 receives signals from themotion sensor 152 and, based on the frequency and/or magnitude of theaccelerations, the mobile communication unit 122 decides whether andwhen to enter or exit a sleep mode. For example, following a period oftime in which no accelerations of sufficient magnitude are detected(i.e., a sensed acceleration magnitude fails to exceed a predeterminedthreshold) or a period of time in which an insufficient number ofacceleration events are detected within an amount of time (i.e., anacceleration frequency fails to exceed a predetermined threshold), thenthe mobile communication unit 122 may decide to enter a sleep mode.

Alternatively, the mobile communication unit 122 may transmit a signalto the base station 104, and the base station 104 may decide whether andwhen to instruct the mobile communication unit 122 to enter the sleepmode based on the transmitted acceleration magnitude or accelerationfrequency signal. Conversely, when an acceleration of sufficientmagnitude is detected (i.e., a sensed acceleration magnitude exceeds apredetermined threshold) or a sufficient number of acceleration eventsare detected within an amount of time (i.e., an acceleration frequencyexceeds a predetermined threshold), then the mobile communication unit122 may decide to exit the sleep mode. Alternatively, the mobilecommunication unit 122 may transmit a signal to the base station 104,and the base station 104 may decide whether and when to instruct themobile communication unit 122 to exit the sleep mode based on thetransmitted acceleration magnitude or acceleration frequency signal.

Under normal operating conditions, the mobile communication unit 122 isconfigured to rely upon the motion sensor 152 so that when no movementis detected for a predetermined period of time, the mobile communicationunit 122 enters a sleep mode. Unfortunately, the mobile communicationunit 122 may unnecessarily remain awake if it is located in closeproximity to the vehicle 102, and undergoes incidental movements, suchas might be experienced if the mobile communication unit 122 were in thepocket of a user relaxing in the vicinity of the vehicle 102 (e.g.,enjoying a picnic, watching a youth soccer match). Accordingly, alimited-response mode may also involve de-sensitizing the internalmotion sensor 152 of the mobile communication unit 122 in addition tosuspending the transmission of ID pulses.

As described above, the base station 104 may be configured to recognizea picnic scenario in which the mobile communication unit 122 remainswithin the authorization zone 138 for an extended period of time and themotion sensor 152 signals indicate that the mobile communication unit122 is actively moving, yet the user initiates no commands—eitheractively of passively—upon the vehicle 102. Upon recognition of a picnicscenario, the base station 104 is configured to command the mobilecommunication unit 122 to enter a limited-response mode. Where themobile communication unit 122 is equipped with a motion sensor 152, andthe mobile communication unit 122 is configured for awakening inresponse to suitable signals received from the motion sensor 152,activation of a suitable limited-response mode for such a mobilecommunication unit 122 may involve de-sensitizing of the internal motionsensor 152 of the mobile communication unit 122 in addition tosuspension of transmission of ID pulses. Desensitizing the internalmotion sensor 152 of the mobile communication unit 122 may involveincreasing the predetermined threshold such that only a fairly stridentmovement would wake up the mobile communication unit 122. This willconserve energy within the second rechargeable battery 126 of the mobilecommunication unit 122, but may still permit relatively large movementsto reawaken the mobile communication unit 122. Upon a subsequentinitiation of a command upon the vehicle 102, the base station 104 mayinstruct the mobile communication unit 122 to return to a normal levelof sensitivity of the motion sensor 152.

Characteristics of the acceleration signal that may be evaluated fordetermining whether criteria associated with the picnic scenario are met(or are no longer met) may include magnitude, frequency, duration andthe integral (i.e., a combination of the magnitude and duration) of theacceleration signal. For example, in one embodiment, the picnic scenariois indicated if the vehicle 102 perceives a sufficient number of wakeups with in a predetermined period of time. A reduced sensitivity of themotion sensor 152 signal may accordingly be configured to distinguishbetween a user's standing up versus merely shifting in his or her seat.Such a distinction would be relevant if standing up were deemed likelyto precede an attempt to gain entry to the vehicle 102, whereasshuffling in the seat would not. In one embodiment, a picnic scenario isindicated by a suitable combination of motion sensor 152 parameters andhow far the mobile transmitter-receiver may have moved within a specificperiod of time.

By recognizing the picnic scenario and taking appropriate remedialaction, such as by desensitizing the motion sensor 152 and/or commandingthe mobile communication unit 122 to enter a sleep mode or another formof power-saving mode, the system may avoid the negative consequences ofunnecessarily activating functions of the vehicle 102 (e.g.,over-exercising of the door locks) and unnecessarily depleting power inthe components of the vehicle communication system 100.

In one embodiment, it is the base station 104 that determines whether apicnic scenario is invoked and accordingly dispatches a command tomodify operation of the mobile communication unit 122. Upon receipt ofsuch a command from the base station 104, the transceiver 124 of themobile communication unit 122 may be caused to perform according to amodified, limited-response duty cycle. It should be appreciated that,while the vehicle communication system 100 is operating in a mode thatrequires relatively immediate response from the mobile communicationunit 122, the transceiver 124 of the mobile communication unit 122operates according to a high-response duty cycle such that thetransceiver 124 remains substantially active at all times, withrelatively little or no periods of inactivity. Accordingly, relativelylittle time lag exists between a transmission of a command signal fromthe first transceiver 110 and a transmission of a response from themobile communication unit 122. When the mobile communication unit 122performs according to the modified, limited-response, duty cycle,however, the transceiver 124 of the mobile communication unit 122 mayremain substantially inactive for the majority of each cycle, withrelatively little time of activity within each cycle. Therefore, arelatively greater time lag exists between transmission of a commandsignal from the first transceiver 110 and the transmission of a responsefrom the mobile communication unit 122.

Accordingly, a high-response duty cycle comprises an active phase thatoccurs without substantial interruption by an inactive phase. Alimited-response duty cycle comprises active phases that are interruptedby periods on inactivity. In one such embodiment, a period of inactivitymay extend for approximately two seconds, during which time thetransceiver 124 is in an inactive state and therefore unable to receivea transmission, such as a command signal transmitted by the base station104. In each active phase occurring between the periods of inactivity,the transceiver 124 of the mobile communication unit 122 is activatedfor a few microseconds (e.g., between approximately one microsecond andapproximately ten microseconds, for approximately three microseconds).During these intervening active periods, the transceiver 124 is capableof receiving communications, including command, polling or challengesignals or other information transmitted by the base station 104. Duringextended time periods of inactive presence within the authorization zone138, the mobile communication unit 122 performs this modified,limited-response, duty cycle, continuously alternating between thelonger periods of deactivation and the relatively brief periods ofactivation. Thus, in accordance with this modified duty cycle, energyconsumption by the mobile communication unit 122 may be substantiallyreduced.

In the event that it becomes necessary or useful to resume two-waycommunications between the base station 104 and the mobile communicationunit 122, the base station 104 transmits a continuous wake-uptransmission pulse lasting for at least as long as the length of eachperiod of deactivation. Accordingly, as soon as the mobile communicationunit 122 enters an active phase in its duty cycle, the mobilecommunication unit 122 encounters the wake-up transmission pulse. Uponreceiving the wake-up transmission pulse, the mobiletransmitter-receiver would take the appropriate action depending on whatthe base station 104 commands the mobile communication unit 122 to do.

A number of scenarios may arise wherein it may be desirable for the basestation 104 to resume communications with the mobile communication unit122 during the picnic mode. For example, whenever a door is opened andclosed, it may be necessary to perform a search for the presence of amobile communication unit 122 within the passenger compartment of thevehicle 102. If there is no mobile communication unit 122 present, thebase station 104 may alert the driver and/or disable certain featuresand functions of the vehicle, in particular to disable the engine orimmobilise the vehicle. To facilitate the search, a wake-up command isissued by the base station 104 whenever a door is opened. Thus, thevehicle communication system 100 provides an energy-saving picnic modewithout compromising relatively continuous communication between thebase station 104 and the mobile communication unit 122.

The vehicle communication system 100 can optionally also provide keylessengine starting for the vehicle 102. By using the ranging data from thetransceivers 110, 112, 114, the electronic control unit 106 candetermine when the mobile communication unit 122 is inside the vehicle102. A control signal can be transmitted to the engine control unit, viathe CAN bus 120, to permit keyless engine starting when a Start buttonis pressed.

The vehicle communication system 100 according to the present inventioncan be further refined. In particular, the electronic control unit 106can be configured to transmit a status signal to the mobilecommunication unit 122. For example, if the base station 104 detects amis-lock scenario, the status signal may instruct the mobilecommunication unit 122 to generate a first user alert. Equally, thestatus signal may instruct the mobile communication unit 122 to generatea second user alert (which is different from the first user alert) whenthe vehicle 102 has been locked. The first and/or the second user alertcould be provided instead of, or in addition to, any notificationprovided by the vehicle 102. The mobile communication unit 122 couldcomprise an audio, optical or haptic output for indicating the vehiclestatus. For example, the mobile communication unit 122 could compriseone or more of the following: LED(s), a text screen or a vibratingmechanism.

The mobile communication unit 122 is also provided with one or morebuttons to allow a user to trigger locking/unlocking of the vehicledoors from outside of the authorization zone 138.

The ultra-wideband (UWB) transceivers 110, 112, 114, 124 describedherein are compliant with IEEE802.15.4a protocol.

The vehicle communication system 100 can monitor time of flight (ToF)communications between the base station 104 and the mobile communicationunit 122 to provide improved security, for example to protect against arelay-station security attack.

A door unlock override switch can be provided to unlock the doors142-148 in the event of an emergency.

The skilled person will understand that various changes andmodifications can be made to the vehicle communication system 100described herein without departing from the spirit and scope of thepresent invention. For example, a welcome lights function could besupported by illuminating an interior and/or exterior vehicle light whenthe mobile communication unit 122 enters the authorization zone 138.

Although the vehicle communication system 100 has been described withreference to the mobile communication unit 122 transmitting the pollingsignal, the system could also operate if the base station 104transmitted the polling signal. For example, the first transceiver 110of the base station 104 may transmit a polling signal which, whenreceived by the remote transceiver 124, initiates communication betweenthe mobile communication unit 122 and the base station 104. In oneembodiment, upon receipt of the polling signal, the mobile communicationunit responds by transmitting a response signal. The response signal isreceived by the first transceiver 110 and the electronic control unit106 validates the response signal.

The mobile communication unit 122 includes a motion sensor 152, such asa gyroscope or an accelerometer, to detect movements of the mobilecommunication unit 122. Signals based on the detected movements may thenbe transmitted to the base station 104 for use in deciding whether, whenand how to facilitate control over vehicle functions. For example, ifthe base station 104 determines that the mobile communication unit 122has been stationary for a predetermined period of time, the base station104 may cause the mobile communication unit 122 to be disabled or toenter a sleep mode. In addition, the base station 104 could transmit adisable signal to deactivate the transceivers 110, 112, 114, 124.Alternatively, the transceivers 110, 112, 114, 124 could be disabledautomatically if they do not receive an authorization signal for apredetermined period of time. The mobile communication unit 122 could beawakened by an activation signal from the motion sensor 152 when itdetects movement. Alternatively, when the vehicle communication systemis operating according to the aforementioned fifth operating mode,wherein the mobile communication unit 122 remains within theauthorization zone 138 for an extended period of time and the motionsensor 152 signals indicate that the mobile communication unit 122 isactively moving, yet the user initiates no commands—either actively ofpassively—upon the vehicle 102, then the base station 104 shall instructthe mobile communication unit 122 to enter the limited-response picnicmode.

Moreover, it will be appreciated that it is not necessary for a vehiclecommunication system 100 according to the present invention to provideall of the operating modes described herein. Rather, one or more of theoperating modes could be embodied in a communication system inaccordance with the present invention.

It will be appreciated that various changes and modifications can bemade to the present invention without departing from the presentinvention. Further aspects of the present invention will be describedwith reference to the following numbered paragraphs.

1. A communication system for facilitating control over a function of avehicle (102), the communication system comprising:

-   -   a base station (104) positioned in the vehicle (102); and    -   a mobile communication unit (122);    -   the base station (104) comprising a first transmitter for        transmitting a signal to the mobile communication unit and a        first receiver for receiving a signal from the mobile        communication unit (122);    -   the base station (104) being configured to determine a location        of the mobile communication unit (122) relative to the vehicle        (102) and to cause the mobile communication unit (122) to        operate in accordance with a limited-response duty cycle when        the location of the mobile communication unit (122) relative to        the vehicle (102) remains substantially unchanged for a        predetermined period of time.

2. A communication system as described in paragraph 1, wherein the basestation (104) is configured to cause the mobile communication unit (122)to operate in accordance with a limited-response duty cycle when thelocation of the mobile communication unit (122) relative to the vehicle(102) remains within an authorization zone (138) for a predeterminedperiod of time.

3. A communication system as described in paragraph 1, wherein the basestation (104) is configured to cause the mobile communication unit (122)to operate in accordance with a limited-response duty cycle when thelocation of the mobile communication unit (122) relative to the vehicle(102) is within an authorization zone (138) and remains relativelyunchanged for a predetermined period of time.

4. A communication system as described in paragraph 1, wherein the basestation (104) is configured to cause the mobile communication unit (122)to operate in accordance with a limited-response duty cycle when thelocation of the mobile communication unit (122) relative to the vehicle(102) is within an authorization zone (138) and the vehicle (102)remains free from interruption for a predetermined period of time.

5. A communication system as described in paragraph 1, wherein themobile communication unit (122) comprises a motion sensor (152)configured for detecting a movement of the mobile communication unit(122) and for sending a signal indicative of the movement.

6. A communication system as described in paragraph 5, wherein the basestation (104) is configured to receive said signal indicative of amotion of the mobile communication unit (122) and to cause the mobilecommunication unit (122) to operate in accordance with alimited-response duty cycle when said signal is indicative of saidmotion satisfying a predetermined limited-response criteria.

7. A communication system as described in paragraph 6, wherein saidpredetermined limited-response criteria comprises freedom from movementsexceeding a threshold level of at least one of a frequency, adistance/magnitude, a velocity, or an acceleration threshold magnitude?

8. A communication system as described in paragraph 5, wherein the basestation (104) is configured to receive said signal is indicative of amotion of the mobile communication unit (122) and to cause the mobilecommunication unit (122) to resume operating in accordance with ahigh-response duty cycle when said signal is indicative of said motionsatisfying a predetermined high-response criteria.

9. A communication system as described in paragraph 8, wherein thepredetermined high-response criteria is based on a frequency of saidmotion.

10. A communication system as described in paragraph 8, wherein thepredetermined high-response criteria is based on a magnitude of saidmotion.

11. A communication system as described in paragraph 5, wherein the basestation (104) is configured to cause a sensitivity of the motion sensor(152) to be adjusted.

12. A communication system as described in paragraph 11, wherein thebase station (104) is configured to cause a sensitivity of the motionsensor (152) to be adjusted when the location of the mobilecommunication unit (122) relative to the vehicle (102) remainssubstantially unchanged for a predetermined period of time.

13. A communication system as described in paragraph 11, wherein thebase station (104) is configured to cause a sensitivity of the motionsensor (152) to be adjusted when the location of the mobilecommunication unit (122) relative to the vehicle (102) remains within anauthorization zone (138) for a predetermined period of time.

14. A communication system as described in paragraph 11, wherein thebase station (104) is configured to cause a sensitivity of the motionsensor (152) to be adjusted when the location of the mobilecommunication unit (122) relative to the vehicle (102) is within anauthorization zone (138) and remains relatively unchanged for apredetermined period of time.

15. A communication system as described in paragraph 11, wherein thebase station (104) is configured to cause a sensitivity of the motionsensor (152) to be adjusted when said signal is indicative of saidmovement satisfying a predetermined limited-response criteria.

16. A communication system as described in paragraph 15, wherein saidpredetermined limited-response criteria comprises freedom from movementsexceeding a threshold acceleration magnitude.

17. A communication system as described in paragraph 15, wherein thepredetermined limited-response criteria is based on a frequency of saidmovement.

18. A communication system as described in paragraph 15, wherein thepredetermined limited-response criteria is based on a magnitude of saidmovement.

19. A communication system as described in paragraph 15, wherein thepredetermined limited-response criteria is based on a duration of saidmovement.

20. A communication system as described in paragraph 1, wherein the basestation (104) is configured for determining a location of the mobilecommunication unit (122) relative to the vehicle (102) based on a timeof flight of communications between the mobile communication unit (122)and three or more transceivers (110) positioned in the vehicle (102).

21. A communication system as described in paragraph 20, wherein thebase station (104) is configured for determining a location of themobile communication unit (122) relative to the vehicle (102) based on atime of flight of an ultra-wide band communication between the mobilecommunication unit (122) and the three or more transceivers (110)positioned in the vehicle (102).

22. A method of facilitating control over a function of a vehicle (102)comprising:

-   -   providing a base station (104) positioned in the vehicle (102)        and a mobile communication unit (122), the base station (104)        comprising a first transmitter and a first receiver;    -   transmitting a signal from the first transmitter to the mobile        communication unit (122);        receiving a signal from the mobile communication unit (122); and    -   determining a location of the mobile communication unit (122)        relative to the vehicle (102); and    -   when the location of the mobile communication unit (122)        relative to the vehicle (102) remains substantially unchanged        for a predetermined period of time, causing the mobile        communication unit (122) to operate in accordance with a        limited-response duty cycle.

23. A method of facilitating control over a function of a vehicle (102)as described in paragraph 22, wherein said causing the mobilecommunication unit (122) to operate in accordance with alimited-response duty cycle is performed when the location of the mobilecommunication unit (122) relative to the vehicle (102) remains within anauthorization zone (138) for a predetermined period of time.

24. A method of facilitating control over a function of a vehicle (102)as described in paragraph 22, wherein said causing the mobilecommunication unit (122) to operate in accordance with alimited-response duty cycle is performed when the location of the mobilecommunication unit (122) relative to the vehicle (102) is within anauthorization zone (138) and remains relatively unchanged for apredetermined period of time.

25. A method of facilitating control over a function of a vehicle (102)as described in paragraph 22, wherein said causing the mobilecommunication unit (122) to operate in accordance with alimited-response duty cycle is performed when the location of the mobilecommunication unit (122) relative to the vehicle (102) is within anauthorization zone (138) and the vehicle (102) remains free frominterruption for a predetermined period of time.

26. A method of facilitating control over a function of a vehicle (102)as described in paragraph 22, further comprising detecting a movement ofthe mobile communication unit (122) and sending a signal indicative ofthe movement.

27. A method of facilitating control over a function of a vehicle (102)as described in paragraph 22:

-   -   further comprising receiving said signal indicative of a motion        of the mobile communication unit (122);    -   wherein said causing the mobile communication unit (122) to        operate in accordance with a limited-response duty cycle is        performed when said signal is indicative of said motion        satisfying a predetermined limited-response criteria.

28. A method of facilitating control over a function of a vehicle (102)as described in paragraph 22, further comprising:

-   -   receiving said signal indicative of a motion of the mobile        communication unit (122); and    -   when said signal is indicative of said motion satisfying a        predetermined high-response criteria, causing the mobile        communication unit (122) to resume operating in accordance with        a high-response duty cycle.

29. A method of facilitating control over a function of a vehicle (102)as described in paragraph 26:

-   -   wherein said detecting a movement of the mobile communication        unit (122) is performed using a motion sensor (152);    -   further comprising causing a sensitivity of the motion sensor        (152) to be adjusted.

30. A method of facilitating control over a function of a vehicle (102)as described in paragraph 22, wherein said determining a location of themobile communication unit (122) relative to the vehicle (102) isperformed based on a time of flight of communications between the mobilecommunication unit (122) and three or more transceivers (110) positionedin the vehicle (102).

31. A vehicle (102) having a communication system, or being adapted toperform a method as described in paragraph 1 or 22.

1. A communication system for facilitating control over a function of avehicle, the communication system comprising: a base station positionedin the vehicle; and a mobile communication unit comprising a motionsensor configured for detecting a movement of the mobile communicationunit and for outputting a signal indicative of the movement; the basestation comprising a first transmitter for transmitting a signal to themobile communication unit and a first receiver for receiving a signalfrom the mobile communication unit; the base station being configured todetermine a location of the mobile communication unit relative to thevehicle and to cause the mobile communication unit to operate inaccordance with a limited-response mode when the location of the mobilecommunication unit relative to the vehicle remains substantiallyunchanged for a predetermined period of time, and wherein the basestation is configured to cause a sensitivity of the motion sensor to beadjusted.
 2. The communication system of claim 1, wherein the basestation is configured to cause the mobile communication unit to operatein accordance with the limited-response mode when at least one of: (i)the location of the mobile communication unit relative to the vehicleremains within an authorization zone for a predetermined period of time;(ii) the location of the mobile communication unit relative to thevehicle is within an authorization zone and remains relatively unchangedfor a predetermined period of time; and (iii) the location of the mobilecommunication unit relative to the vehicle is within an authorizationzone and the vehicle remains free from interruption for a predeterminedperiod of time. 3-5. (canceled)
 6. The communication system of claim 1,wherein the base station is configured to receive said signal indicativeof the movement of the mobile communication unit and to cause the mobilecommunication unit to operate in accordance with the limited-responsemode when said signal is indicative of said motion satisfying apredetermined limited-response criteria.
 7. The communication system ofclaim 6, wherein said predetermined limited-response criteria comprisesfreedom from movements exceeding a threshold level of at least one of afrequency, a distance/magnitude, a velocity, or an accelerationthreshold magnitude.
 8. The communication system of claim 1, wherein thebase station is configured to receive said signal indicative of themovement of the mobile communication unit and to cause the mobilecommunication unit to resume operating in accordance with ahigh-response duty cycle when said signal is indicative of the movementsatisfying a predetermined high-response criteria.
 9. The communicationsystem of claim 8, wherein the predetermined high-response criteria isbased on a frequency of said movement or on a magnitude of saidmovement. 10-12. (canceled)
 13. The communication system of claim 1,wherein the base station is configured to cause the sensitivity of themotion sensor to be adjusted when at least one of: (i) the location ofthe mobile communication unit relative to the vehicle remains within anauthorization zone for a predetermined period of time; and (ii) thelocation of the mobile communication unit relative to the vehicle iswithin an authorization zone and remains relatively unchanged for apredetermined period of time.
 14. (canceled)
 15. The communicationsystem of claim 1, wherein the base station is configured to cause thesensitivity of the motion sensor to be adjusted when said signal isindicative of said movement satisfying a predetermined limited-responsecriteria.
 16. The communication system of claim 15, wherein saidpredetermined limited-response criteria comprises freedom from movementsexceeding a threshold acceleration magnitude and/or is based on one ormore of a frequency of said movement, a magnitude of said movement,and/or a duration of said movement. 17-19. (canceled)
 20. Thecommunication system of claim 1, wherein the base station is configuredfor determining the location of the mobile communication unit relativeto the vehicle based on a time of flight of communications between themobile communication unit and three or more transceivers positioned inthe vehicle.
 21. The communication system of claim 20, wherein the basestation is configured for determining the location of the mobilecommunication unit relative to the vehicle based on a time of flight ofan ultra-wide band communication between the mobile communication unitand the three or more transceivers positioned in the vehicle.
 22. Thecommunication system of claim 1 wherein the limited-response modecomprises the mobile communication unit operating in accordance with alimited-response duty cycle.
 23. A method of facilitating control over afunction of a vehicle, the method comprising: providing a base stationpositioned in the vehicle and a mobile communication unit, the basestation comprising a first transmitter and a first receiver; detecting amovement of the mobile communication unit and outputting a signalindicative of the movement via a motion sensor; transmitting the signalfrom the first transmitter to the mobile communication unit; receivingthe signal from the mobile communication unit; and determining alocation of the mobile communication unit relative to the vehicle,wherein, when the location of the mobile communication unit relative tothe vehicle remains substantially unchanged for a predetermined periodof time, causing the mobile communication unit to operate in accordancewith a limited-response mode.
 24. The method of claim 23, wherein saidcausing the mobile communication unit to operate in accordance with thelimited-response mode is performed when at least one of: (i) thelocation of the mobile communication unit relative to the vehicleremains within an authorization zone for a predetermined period of time;(ii) the location of the mobile communication unit relative to thevehicle is within an authorization zone and remains relatively unchangedfor a predetermined period of time; and (iii) the location of the mobilecommunication unit relative to the vehicle is within an authorizationzone and the vehicle remains free from interruption for a predeterminedperiod of time. 25-27. (canceled)
 28. The method of claim 23, furthercomprising: receiving the signal indicative of the movement of themobile communication unit; wherein said causing the mobile communicationunit to operate in accordance with a limited-response mode is performedwhen the signal is indicative of said movement satisfying apredetermined limited-response criteria.
 29. The method of claim 23,further comprising: receiving the signal indicative of the movement ofthe mobile communication unit; and when the signal is indicative of saidmovement satisfying a predetermined high-response criteria, causing themobile communication unit to resume operating in accordance with ahigh-response duty cycle.
 30. (canceled)
 31. The method of claim 23,wherein said determining a location of the mobile communication unitrelative to the vehicle is performed based on a time of flight ofcommunications between the mobile communication unit and three or moretransceivers positioned in the vehicle.
 32. The method of claim 23,wherein the limited-response mode comprises causing the mobilecommunication unit to operate in accordance with a limited-response dutycycle.
 33. A vehicle comprising the communication system of claim
 1. 34.A vehicle configured to perform the method of claim 23.